ExAO coronagraph Planet Imager(ExPI) for 12-meter LOT

Transcription

1 ExAO coronagraph Planet Imager(ExPI) for 12-meter LOT Jiangpei Dou Representing the ExPI Group Deqing Ren 2,1, Yongtian Zhu 1, Xi Zhang 1, Gang Zhao 1, Chengchao Liu 1, Jing Guo 1, Feng Yang 1, Gang Wang 1, Sizhen Liu 1, Chao Yang 1, Zijian Han 1, Ziyue Wang 1, Yuliang Shen 1 1. NIAOT/NAOC 2. CSUN, USA

2 1. Exoplanet Imaging: Current Status Scientific Drive A critical step to terrestrial life signals: Separating planet s light from star Open the window for spectroscopy Answer are we alone in the universe? Extending the Copernican revolution Challenging the Planet Formation theory(core accretion, gravitational instability, outward migration ) LkCa 15 b, c Currie et al Sallum et al Forming & Accreting protoplanets

3 1. Exoplanet Imaging: Current Status To study the whole process of Planet Evolution (All age planets) Mass uncertainty: depending upon the initial conditions established during their formation a) Cooling model: HR 8799 b (5-11 M J ), c, d, e(7-13 M J ), see Marois et al b) Evolution models + dynamical stability HR 8799 b (6-7 M J ), c, d, e(7-10 M J ), see Currie et al Marley ApJ 2007; Dou& Ren ApJ 2016

4 1. Exoplanet Imaging: Current Status Core science of 8-10 meter telescope and future 30-meter class GSMTs Suitable for the direct imaging (detection can be realized with 10-minutes integrating time with one 8-m telescope, if the planet exists) ExAO coronagraph technique developed in GPI, SPHERE and SCExAO Focusing on the Young Giant exoplanets around bright stars Current contrast 10-6, ultimate goal better than Commissioning Macintosh et al. 2006; 2014 Fusco et al. 2006; 2014 Guyon et al. 2012; Groff et al. 2015

5 Technique comparison GPI s coronagraph: Apodized pupil Large IWA(inner working angle):~5 λ/d; difficult to resolute planets nearby the primary GPI/SPHERE: two-dm configuration(woofer &Twitter ) Complicated system; DM with bad actuators; None-common-path aberration (NCPA) GPI introduced post-interferometer, low throughput and extra phase aberration SPHERE, phase retrieval algorithm Potential limitation to achieve final goal of 10-7 ExAO coronagraph Planet LOT High performance and large stroke DM(no bad actuator) Vortex coronagraph(small IWA down to~2 λ/d) Polarimetry(precision of 10-3 ) IRS technique and O-IRS data reduction(small IWA with high S/N) Aperture size is 1.5 times larger than Gemini/GPI High resolution, contrast better than 10-7 at marcsec First ExAO on a segment mirror telescope Build solid foundation for future GSMT Macintosh et al. 2014

6 Aimed contrast vs angular separation (IWA) Young giant, self emission in infrared EDICT(15) Mature planets (reflection) GPI (15) GPI goal LOT 1st Jupiter Earth LOT final goal Space mission Neptune Blue region: Mature planets (GPI cannot image these planets)

7 2. ExAO coronagraph Planet Imager(ExPI) Scientific goals: Giant Jupiter-size/mass exoplanets at all ages, AU from stars located in 100pc Including both cool(t eff <800K)and young (10MYr~1GYr)planets General high-resolution or high-contrast imaging science for the whole Astronomical Society Performance: Stage I: Contrast of 10-6 ~10-7,at both H and K band; Stage II: Contrast of 10-7 ~10-9,at J and I band.

8 ExPI Layout ExAO + Coronagraph + Polarimetry + Post Image Processing OAP2 f=2250mm F#50 FM2 DM 820 (30 x 30,C.A. 45 mm) Broad-band filters(i, J, H, K) Fore-optics WFS: 29x29 WFS FM1 Dichroic Beamsplitters CCD Polarimetry OAP4 f=1500mm FM5 FM4 Tip-Tilt Vortex coronagraph OAP1 (f= 652.5mm) TF(Nasmyth focus,f#14.5) OAP3 f=500mm High-contrast Imaging FM3 Layout: physical size of 1.5 x 1.2 x 0.5m

9 Unique feature: 1) ExAO Stable and high-quality DM (No woofer), compact and efficient Non-common optical path correction: SPGD algorithm ALPAO 820 DM Dou et al Ren et al. PASP 2012 Ren & Dong, Opt. Eng. 2012

10 ExAO observation (Visiting instrument) ESO 3.6-m NTT 6 nights 3.6-m NTT 0.9 x 0.6 x 0.3 m 3 NGS(Vmag down to 8) LSO NorthernSphere Dou, Ren, & Zhu 2015 APO 3.5-m ARC Apache Point 3.5-m telescope ,3 times Diffraction limited 0.09 (seeing1.4 ) Jul 14-20, AO@NB Ex-AO@NA zet Her A/B McDonald 2.7-m Smith Sep, 2016, 4 nights(dr. Brendon Bowler) Updated to277actuator DM VMag of 6(next step 8) ExAO@Coude kapp And HD Observation contrast:10-5 AO 开 Supported by NSFC Major International collaboration More science data will come in Dec., 2016 & Jan., 2017

11 LOT: Performance LOT aperture and PSF Aperture PSF in theory LOT ExAO corrected PSF Video YAO software Ali seeing(avg. 0.8 ),Wind speed (6m/s) ExAO configuration:dm-820(30x30), WFS(29x29), Central Obstruction 12% (diameter) Rigaut & Van 2013 Table:Strehl ratio vs wavelength and Mag Stage I Mv H ~ K Stage II (backu p) M H J I

12 2) Vortex Coronagraph Star L1 L2 L3 EP TF Planet M: Vortex Mask L4 PS Detector Dou et al. ApJ 2016 Contrast:10-6 ~ ~9 λ/d Guo et al. 2016;Liu et al. 2016;Dou et al a, b;wang et al. 2011

13 Achieved contrast In the λ/d Vortex mask Layout Entrance pupil Pupil plane Stellar light Image plane L1 L2 L3 L4 Phase mask (LCP) Lyot Contrast Contrast: without OVC Contrast: with OVC Contrast: Lab test at 633nm Contrast: Lab test at 1520nm Relative Intensity (log 10 ) Liu, Ren, Zhu, Dou, COL Angular Distance (6 /D) Observation data will come in Dec., KPNO

14 3) Polarimetry Imaging Achieve precision:10-3 (single); 10-5 (multiple) x Stokes I Stokes Q/I Pixels Pixels Pixels Pixels Stokes U/I Stokes V/I Pixels Pixels Pixels Pixels Measured Stokes High-contrast in lab PSF(star+planets) Liu, Ren, Zhu, Dou & Guo, RAA 2016 PSF(Q) Guo et al, RAA 2016 PSF(U) Dou et al a, b;wang et al Proposed to demonstrate on 2.4-meter and 4 meter class telescopes in next 2-3 years; Supported by NSFC, XDA/CAS, Special Fund

15 4) Data reduction Unique IRS and O-IRS High S/N at small IWA; Little attenuation for planets at small angular separation. HR8799 b, c, d, e LOCI OIRS Dou, Ren & Zhao, et al., ApJ 2015, 802, 12 Ren, Dou, & Zhu, et al., ApJ 2012

16 Aimed contrast performance Vmag 5~10,H band: 1 hour ; 10 minutes exposure(5): ; Vmag 5,I band: 1 hour ; 10 minutes exposure: ~ ;

17 Observation time requirement 10%Overhead(read time, targeting, bad weather etc.) Mature/Cool Planets Lyon & Clampin 2012; Dou et al Jupiter Earth Brown & Burrow 1990 CNT (AU) -2 Fig: Mag 5 Star, one-hour exposure time 30pc, <6AU 1 R J,45pc, <10AU 2 R J

18 Young Giant(optimal & min): 360(120) 120Myr Young Stars Mawet et al Fig. the distribution of target stars 10 minutes exposure Survey 60(20)hours Expected detection: 5%,~18(6); 2-4 confirmation(18*1/6*3~9)and highprecision observation (18*2=36,min12) Total:( )*1.1=116(39)hours Long TRENDS Survey (30~50targets): 1.5 hours/target, 66 in total

19 Targets (Young, mature and RV Long Trends) Observation time requirement: Optimal: 1000 targets 941 hours, 118 nights, 23.6 nights/year(5 years) Minimum: 560 targets 650 hours, 82 nights, 16.4 nights/year(5 years)

20 3. Configuration and budgets Budgets in total of M CNY(~3.5 M USD) Hardware DM TTM WFS-Visible Quote ALPAO-820 1set,PI S-330.2SL 1 set,first Light,Ocam2K-S-N Workstation Coronagraph Polarimetry NIR camera Optics Mechanics Vis-Camera WFS-NIR Total 4x 12 core Intel Xeon E5-2687W v4 3.0GHz Vortex,C.A> 50x50mm,2-stage LCVR,Wollaston, etc Princeton Instrument NIRvana 640-LN:First Light C-Red OAPM, FM etc. Supporting and interface ANDOR ikon DU934P-BR-DD 1 set, First light,c-red

21 Ex-AO will also provide service for astronomical society High-resolution Quasars; Solar objects (moon); Galaxy and etc. Faint stars: Seeing requirement 0.66 (optimal) WFS:5x5 V-Mag14 star Strehl ratio of K A significant compensation to GPI,SPHERE Kepler candidate confirmation Vmag 14,K band: 1 hour ;

22 4. Second Generation Instrument LGS-MCAO Performance: FOV<2 x2 ; Mv<19 Targets: Planets around faint stars (Mv<19, GPI/SPHERE Vmag<10; Keck AO only 349 actuator) Follow-up observation of planets candidates by transit or RV General science with requirement of large FOV Wizinowich et al Unique feature: Pupil-Transformation MCAO: Ren, Zhang, Dou, Zhu et al Two- 820 DM, DM1 conjugated to telescope pupil (GLAO); DM2 to high-altitude (depending on the 3-D seeing profiler test result)

23 5. Summary & Conclusions Direct Imaging of Exoplanets has challenged the planet formation theory; Evolution model needs to improve by imaging all-age planets, especially the mature planets ExPI for LOT will be able to make important contribution ExAO for LOT is a mature technique AO with 97-actuator and 277-actuator DMs. AO with 468 actuator will be available in next year. Our Non-common optical path algorithm is an unique technique optimized for high-resolution and high contrast imaging. Visiting observation experience in recent years The Ex-AO with 820-actuator DM for the 12-m telescope can be built based on current technique (4 Xeon CPUs and so on). High-contrast imaging technique We have developed vortex coronagraph, optimized for small IWA. We have developed our IRS data reduction technique. We have developed our polarization imaging technique: 10-3 contrast gain. Combined with our Ex-AO, coronagraph, Polarimetry and IRS, we aim to achieve 10-7 in the NIR for young and 10-8 in short wavelength for all-age exoplanet imaging.

24 Two purpose to build large telescopes: 1) High special resolution (diffraction limited), otherwise the resolution is similar to a 100mm telescope due to seeing limitation 2) High energy gathering (faint stars) Therefore, diffraction limited performance provided by ExAO is suggested to be used in future generation instruments